SnB: Crystal Structure Determination via Shake-and-Bake Several years ago we developed Shake-and-Bake, a direct methods phasing algorithm for molecular structure determination based on Hauptman's minimal principle. We have recently developed SnB, a computer program based on Shake-and-Bake, which has been used successfully to solve more than two dozen structures in a variety of space groups. This proposal includes the details of our SnB system, including its structure, system requirements, running times, and the rationale for coding in a combination of C and Fortran. We request computational resources to continue and extend the development of this system. A brief summary of successful SnB applications is provided in this proposal. These include i) solving two previously unknown 100-atom structures, and ii) re-solving crambin(a structure containing the equivalent of approximately 400 fully occupied atomic positions) for the first time with a direct methods technique.